Saxophonist Miguel Zenón in peak form

The ingeniously paced, handsomely played set that alto saxophonist Miguel Zenón offered Thursday night at the Jazz Showcase very nearly summed up the man’s appeal in small-group settings.

For if Zenón had affirmed has ability to hold his own in an orchestral setting last February, when he fronted the Chicago Jazz Ensemble at the Harris Theater, this time he led his quartet in expansive performances of both new and familiar repertoire. Virtually every piece in his first set emerged a model of pacing and architectural clarity, themes appearing and re-appearing at carefully chosen moments, instruments entering and exiting the ensemble texture for maximum dramatic effect. Yet, somehow, the music sounded free and spontaneous while conveying unmistakable structure and form.

Not surprisingly, the heart of the set was built on scores from Zenón’s most recent recording, “Alma Adentro,” in which Zenón re-imagined classic popular songs of his Puerto Rican heritage through the prism of jazz improvisation. As strong as this music sounded on disc, however, in some ways it proved still more effective in this performance, thanks largely to the bloom of Zenón’s tone in full-throated passages and the delicacy of his sound elsewhere.

In “Incomprendido,” the plaintive quality of Zenón’s lines and the tenderness of his timbre could disarm the most hard-hearted listener, yet not for a moment did Zenón dip into sentimentality. Not since the melting lyricism of Art Pepper have I heard alto playing as emotionally open and searing as this, even if Zenón’s sound remains fuller, sharper and less fragile than Pepper’s. Moreover, the content of Zenón’s solos — which he packed with flurries of notes one moment, long-held pitches the next — attested to Zenón’s determination to keep developing this material and finding new ideas within it.

Just when one presumed the “Alma Adentro” title track was reaching its close, for instance, Zenón caught listeners by surprise with an extended, unaccompanied statement transforming the melody once more. The lyrical grace of this coda counterbalanced the softly murmuring passages that had opened the piece and attested to Zenón’s ability to build a sustained performance.

Not that everything in this set proceeded quite so meticulously. Zenón and the quartet opened with an original new work, “True Culture and Tradition,” and only Zenón himself sounded fully assured in this material. Pianist Luis Perdomo, bassist Ricardo Rodriguez and drummer Henry Cole were feeling their way through this music, no surprise considering its many complexities, including remarkably elastic tempos.

Through most of the set, though, Cole produced characteristically taut, driving rhythm; and bassist Rodriguez offered lithe, melodically inspired solos.

The past few years have been dramatic for Zenón, and not only because he won a MacArthur Fellowship, or “genius grant,” in 2008. More important, recordings such as “Alma Adentro” and “Esta Plena” have enriched the language of jazz with the vocabulary of Puerto Rican music, and vice versa. That much becomes freshly apparent every time he performs, his inquisitiveness in both realms clear to hear at the Jazz Showcase.